Some people did, but they were largely downvoted. The most upvoted comments focused on why they felt she was unsuitable to represent Minecraft, as you can read here
. I have no idea who she is as I've never seen one of her videos, so I have no axes to grind, but it is highly questionable that someone with no experience was hired to organise a convention based off of the fact that she made Minecraft videos on Youtube.
Basically, between this, the Yogscast thing, the goings on at the Deadmaus party, and the fact that the convention appears to have been poorly organised in general, Minecon probably wont be remembered as a roaring success.